Supervisors: Frank-Thorsten Krell (The Natural History Museum), Richard Ellis, Simon Potts
Dung beetles (Coleoptera: Scarabaeidae) play a vital role in nutrient recycling by burying dung. This has important ramifications for soil fertility- Since the diversity and abundance of coprophagous insects is likely to affect the efficiency of their role in the ecosystem, it is important to understand how they are affected by human influence on habitats and landscapes
- Little is understood about nutrient cycling in natural ecosystems, and as there is rapid human population growth in West Africa, more and more of the land area is used for cultivation of crops. Agriculture in this region is typically of ‘slash-and-burn’ type, which has a negative impact on soil fertility
- The derived savanna in the Ivory Coast is burned almost completely every year, to maintain grazing land for domestic animals and to encourage game
- Fire plays a significant role in determining vegetation structure in savannas, and the burning of vegetation significantly affects the microclimate at ground level. The albedo of the soil changes, which causes soil surface temperatures and thermal amplitudes to increase after burning
- Fire is also used in the forest, to clear the land for agricultural use, and well-structured secondary forest takes over fifty years to reappear
- The dung-ball rolling behaviour displayed by telecoprids has high energetic requirements, and is therefore more efficiently carried out under high temperatures. Thus, we would expect the guild structure of coprocenoses to be strongly affected by the microclimate present around the dung, and therefore to differ between areas with different fire regimes
- This study assesses the impact of fire, both in savanna and forest habitats, on the guild structure of coprocenoses in Côte d’Ivoire.
The main objectives of this study are to:
- Explore the effects of grassland management (specifically annual burning) on the guild structure, species composition and abundance of coprophagous beetle communities in cattle dung
- Explore the effects of fire in forest management (specifically burning as a part of agriculture) on the guild structure, species composition and abundance of coprophagous beetle assemblages in cattle dung
- Examine how fire changes the habitat parameters to which dung beetles respond
- Extrapolate, from the data obtained, the landscape effects of burning on dung beetle-mediated nutrient cycling in West Africa.
1kg samples of cattle dung were exposed for 10-12 hours in three forest sites (secondary forest, coffee plantation and yam field) to assess the impact of agricultural land use on dung beetle assemblages in 2001 and 2002. The same method was used on three savanna sites (burned, unburned and cut – the cut site mimicking the removal of vegetation caused by burning without using fire) in the dry season of 2002 (January – when burning normally occurs) and in the rainy season of 2002 (April/May).
OUTPUTS
The findings will contribute to the general understanding of dung beetle ecology, and how humans affect important ecosystem processes in indirect ways.
The study is funded by a grant from the German Federal Ministry of Education and Research (BMBF) and is a part of the BIOTA project. The work is carried out in cooperation with the Natural History Museum (London), the Centre Suisse de Recherches Scientifiques (Abidjan), the Alexander-König Institute (Bonn), and the National Museums of Kenya (Nairobi).
